RFID bridge antenna

ABSTRACT

A package for at least two objects includes RFID bridge antennas, having RF antenna elements, for wirelessly communicating data between a tag associated with each object and a reader. An electromagnetic carrier signal transmitted by the reader antenna is received by one of the RF antenna element and retransmitted to the tag antenna by the other RF antenna element, increasing the distance over which the tag can communicate with the reader. Where the tag is attached to a packaged object, the RFID bridge antenna may be included in the package to allow wireless data communication between the tag and a reader. The reader may also be located external to the package. For example, one of the RF antenna elements may be attached to a label on the package, allowing data stored in the tag to be extracted by the external reader.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.12/630,316, filed Dec. 3, 2009, now U.S. Pat. No. 7,973,662 which is adivisional application of U.S. application Ser. No. 11/387,176, filedMar. 23, 2006, now U.S. Pat. No. 7,642,916.

BACKGROUND

A common trend in machine design, particularly in the office equipmentindustry, is to organize a machine on a modular basis, wherein certaindistinct subsystems of the machine are bundled together into moduleswhich can be readily removed from the machine and replaced with newmodules of the same or similar type. A modular design facilitates greatflexibility in the business relationship with the customer. By providingsubsystems in discrete modules, also known as “customer replaceableunits” or CRUs, visits from a service representative can be made veryshort, since all the representative has to do is remove and replace adefective module. Actual repair of the module may take place remotely atthe service provider's premises. Further, some customers may wish tohave the ability to buy modules “off the shelf;” such as from anequipment supply store. Indeed, it is possible that a customer may leasethe machine and wish to buy a supply of modules as needed. Further, theuse of modules, particularly for expendable supply units (e.g., copierand printer toner bottles) are conducive to recycling activities.

In order to facilitate a variety of business arrangements amongmanufacturers, service providers, and customers, it is known to providethese modules with electronically-readable memory devices, also known as“customer replaceable unit monitors” or CRUMs, which, when the module isinstalled in the machine, enable the machine to both read informationfrom the CRUM and also write information to the CRUM. The informationread from, or written to, the CRUM may be used by the machine to performvarious functions. For example, U.S. Pat. No. 6,016,409 entitled “SystemFor Managing User Modules in a Digital Printing Apparatus”, which isincorporated by reference herein in its entirety, describes various datathat may be stored in a CRUM and various functions that may be performedusing this data.

The use of CRUMs in a machine requires that the machine include a meansfor communicating data between the CRUMs and the control circuitryresident in the machine. This may be accomplished wirelessly. Forexample, U.S. Pat. No. 6,377,764 issued Apr. 23, 2003 and entitled“Method and Apparatus for Communication, Without A Solid Medium, AmongControl Boards in a Printing Apparatus,” which is incorporated byreference herein in its entirety, describes a digital printing apparatusin which one or more modules has a board therein, which is able tocommunicate with another board within the apparatus by infrared or otherwireless communication. In another example, U.S. Pat. No. 6,351,621 toRichards et al., describes a printer or copier having a removablemodule, such as a marking material supply module or a marking devicemodule, that is provided with a CRUM. The non-volatile memory of theCRUM is accessed through a wireless interface, such as a radio frequencyidentification (RFID) system, which is also associated with the module.The memory can be accessed, through wireless means, either by theprinter or copier itself or by an external device.

Wireless identification systems (e.g., RFID systems) typically includetwo sub-assemblies: a tag (also known as a transponder) and a reader(also known as an interrogator, transceiver, or coupler). The tag istypically attached to an object, and includes, among other components,an antenna and an integrated circuit (IC) device. Stored within the ICdevice is information related to the object to which the tag isattached. While this information usually includes identification datafor the object, it may include other information related to, or used by,the object (e.g., tracking information, usage information, computercode, etc.). For example, the object may be a CRU and the tag may be aCRUM.

In operation, the antenna on the tag receives incoming data signalssuperimposed on a modulated carrier signal, which is provided by anantenna on the reader. In response to the incoming data signals, the tagsuperimposes data from the IC device onto the carrier signal by changingits own circuit impedance. In some tags, known as passive tags, thecarrier signal is used to provide operating power for the tag. In othertags, known as active tags, at least some of the operating power for thetag is provided by a source other than the carrier signal (e.g., abattery).

The reader forms an interface between the tag and a host such as acomputer. The reader generally includes an integrated circuit chip andassociated circuitry that allows it to communicate with both the tag andthe host computer. Typically, there is a predefined command set used bythe host computer to control the reader, which passes the commands tothe tag via the modulated carrier signal. The reader generates themodulated carrier signal to transmit data to the tag, and receives datafrom the tag by detecting the loading effects of the tag on the carriersignal.

Any given tag and reader combination will communicate data over alimited distance. For example, an RFID system that conforms toInternational Standards Organization (ISO) Standard 14443-2B (13.56mega-Hertz (MHz)) is ideal for communicating over distances of between 0millimeters (mm) to 30 mm. If a system is designed to operate in the mmto 20 mm range, it is unlikely this system will work in the 40 mm to 50mm range. Problematically, it is unlikely that the designedcommunication range can be maintained at every desired point of access(e.g., during production, packaging, shipping, and installation). Forexample, when a CRU having an attached CRUM is packaged for shipping orstorage, the distance between the CRUM within the package and a readerexternal to the package may be greater than the designed operatingrange. As a result, the CRUM must be removed from the package to placethe reader close enough for data communication between the CRUM andreader.

BRIEF SUMMARY

According to one aspect, there is provided a radio frequencyidentification (RFID) bridge antenna for increasing a distance overwhich a tag can communicate with a reader or coupler. Basically, thebridge antenna comprises at least two radio frequency (RF) antennaelements spaced apart from one another and coupled together by anelectrical conductor. The first of the two RF elements is locatedproximate to the reader antenna and the second RF element is locatedproximate to the tag antenna. An electromagnetic carrier signalgenerated by the reader is transmitted to the first RF antenna elementand is then passed through the conductor to the second RF element,bridging the gap between the tag and reader antennas and increasing thedistance over which the tag can communicate with the reader.

In another aspect, there is provided a machine, such as a printingapparatus, containing at least one customer replaceable module or CRU,such as a printing ink cartridge or toner bottle, the module having aCRUM or tag associated therewith for wirelessly communicating data witha reader. The machine includes a RFID bridge antenna for extending thedistance over which the tag can communicate with the reader. The bridgeantenna includes a local RF antenna element positioned proximate to thereader antenna and a remote RF antenna element positioned proximate tothe tag antenna. The two RF antenna elements are coupled together by aconductor of sufficient length to bridge the gap between the tag andreader antennas and thus enable communication between both the tag andreader over a distance that would otherwise not be possible.

In another aspect, there is provided a package for storing an objecthaving a tag associated therewith for wirelessly communicating data witha reader, wherein the object is placed in a remote location inside thepackage. An RFID bridge antenna is positioned inside the packaged forextending the distance over which the tag can communicate with thereader. The bridge antenna comprises a local RF antenna coil positionedproximate to the reader antenna and a remote RF coil positionedproximate to the tag antenna. An electromagnetic carrier signalgenerated by the reader is transmitted by the reader antenna to thelocal RF coil, this signal being then carried by an electrical conductorto the remote RF antenna coil proximate to the tag antenna. The signalis then retransmitted via the tag antenna to the tag, covering anoverall distance which is significantly greater than would ordinarily bepossible without the bridge antenna. Although the electrical conductorcan be a simple open wire lead, it is preferred that the two RF antennaelements be electromagnetically coupled together using a flexible,low-loss, shielded co-axial cable or coax.

In another aspect, there is provided a package for storing multipleobjects having a tag associated with more than one of the objects forwirelessly communicating data with a single reader, wherein at least oneof the objects is remotely located inside the package. In this case, thereader is provided with at least one reader antenna arranged so as totransmit an electromagnetic carrier signal to multiple tags associatedwith the objects. The tags communicate directly with the reader using asingle RFID bridge antenna or a series of bridge antennas wirelesslycommunicating with a tag associated with at least one of the objects,the bridge antenna or antennas increasing the distance over which thetag or tags can communicate with the reader. The reader may be locatedeither inside or outside of the package.

In still another aspect, there is provided a machine, such as a printingapparatus, including a case or cabinet having a hingeably mounted doorproviding access for storage of at least one consumer replaceable moduleor CRU, such as a bottle containing a printing material, (e.g. liquidink), the bottle having a CRUM or tag including a tag antenna associatedtherewith for wirelessly communicating data to a reader. The module orCRU is remotely located inside the case or cabinet and has its tagantenna in close proximity to the door when the door is closed. An RFIDbridge antenna is mounted to the inner side of the door, such that whenthe door is closed, one of its two RF antenna coils is placed in closeproximity to the container or bottle and its tag while the other RF coilis placed in close proximity to the reader also inside the case orcabinet. In this aspect, the bridge antenna utilizes the door as aco-planar, non-conductive substrate to increase the distance or gap overwhich the tag can communicate with a reader. Also, in this aspect, sinceboth of the bridge antenna coils lie within the same plane on the innerside of the door, the antenna coils can be advantageously incorporatedonto a single substrate such as a PC board, eliminating the need for aflexible cable or coax such as may be required in order to makeconnection between antenna elements that may lie in different planes.

In yet another aspect, there is provided a PC board having asubstantially flat planar surface on which is mounted an electricalcircuit including an RFID bridge antenna comprising at least two RFantenna coils spaced apart a distance from each other and connectedtogether by an electrical conductor. The conductor may be asubstantially flat, low-loss, open wire conductor similar to a twin leadTV cable embedded within the surface of the PC board.

In yet another aspect, there is provided a method for increasing thedistance over which a tag can communicate with a reader comprisingproviding a bridge antenna including at least two RF antenna elements,placing the two RF antenna elements in spaced apart relation, one inproximity to the reader and the other in proximity to the tag, providingan electrical conductor of sufficient length to extend across the gapbetween the tag and the reader and electrically connecting the two RFantenna elements together using the conductor, thereby increasing thedistance over which the tag can communicate with the reader.

BRIEF DESCRIPTION OF THE DRAWING

Referring now to the drawings, which are exemplary embodiments, whereinlike items are numbered alike:

FIG. 1 is a perspective view of an RFID bridge antenna including a pairof RF antenna elements;

FIG. 2 is a similar view of an RFID bridge antenna disposed between areader and a tag antenna;

FIG. 3 is a schematic view of the tag, the reader and the RFID bridgeantenna, showing each in greater detail;

FIG. 4 is a perspective view of a package containing multiple objectsprovided with individual CRU tags communicating with a single readerinside the package using at least one bridge antenna;

FIG. 5 is a perspective view of a package or machine containing multipleobjects or modules provided with CRU tags at least one of which objectsor modules is located in a remote location inside the machine or packageand wherein the tags communicate with a single reader located outsidethe package or machine.

FIG. 6 is a perspective view of a pair of containers or bottles eachprovided with a CRU tag, one located on the side wall of the containeror bottle and the other located within the top of a closure cap;

FIG. 7 is a perspective view of a storage cabinet for a machine, such asa printing apparatus, including supply modules, such as ink bottleshaving a closure cap of the type shown in FIG. 6, wherein the cabinethas a hinged door, the inner side of which is provided with an RFIDbridge antenna for bridging the gap over which a reader inside thecabinet can communicate with the tag on the closure cap;

FIG. 8 is a plan view of a PC board having an RFID bridge antennaembedded within its surface including a low loss twin lead conductor forconnecting the two RF antenna elements or coils together;

FIG. 9 is a schematic view of a machine, such as a printing apparatus,including customer replaceable units (CRUs) with tags (CRUMs) wherein anRFID bridge antenna is advantageously employed to enable communicationbetween the tags and a reader.

DETAILED DESCRIPTION

Referring to FIGS. 1-3, there is shown the basic structure of an RFIDbridge antenna 10 for increasing a distance over which a tag (also knownas a transponder) 12 can communicate with a reader (also known as aninterrogator, transceiver, or coupler) 14. As shown in FIG. 1, thebridge antenna 10 comprises two RF antenna elements or coils 16 and 18spaced apart from one another and electrically coupled together by anelectrical conductor 20. As shown in more detail in FIG. 2, one of theRF coils 16 is located proximate to the reader 14 while the other RFcoil 18 is located proximate to the tag 12. The conductor 20 ispreferably a flexible, low loss, shielded co-axial cable, such as a 50ohm coax, for example, and is connected to the base of each RF coil 16,18 using a conventional coaxial terminals 22. The tag 12 is typicallyattached to an object (not shown), and includes a tag antenna 24 and anintegrated circuit (IC) device 26 (see FIG. 3). Stored within the ICdevice 26 is information related to the object to which the tag 12 isattached. While this information usually includes identification datafor the object, it may include other information related to, or used by,the object, as will be described in further detail hereinafter. It iscontemplated that the object to which the tag 12 is attached may be anytangible item. In one embodiment, described hereinafter with respect toFIG. 9, the object includes a replaceable module for a machine, alsoreferred to as a CRU (Customer Replaceable Unit), and the tag 12 isconfigured as a CRUM (Customer Replaceable Unit Monitor).

As shown in greater detail in FIG. 3, the reader 14 forms the interfacebetween the tag 12 and a host processor (e.g., a computer) 28. Thereader 14 generally includes a reader antenna 30, an integrated circuitdevice 32, and other associated circuitry that allows the reader 14 tocommunicate with both the tag 12 and the host processor 28. Typically,there is a predefined command set used by the host processor 28 tocontrol the reader 14, which passes the commands to the tag 12 via amodulated, electromagnetic carrier signal transmitted from the readerantenna 30. The reader 14 generates the modulated carrier signal totransmit data to the tag 12, and receives data from the tag 12 bydetecting loading effects of the tag 12 on the carrier signal.

As used herein, a reader is any device that generates a modulated,electromagnetic carrier signal to be received by a tag, and receivesdata from the tag by detecting loading effects on the carrier signal.Similarly, a tag is any device that receives a modulated,electromagnetic carrier signal transmitted by a reader and superimposesdata onto the carrier signal by load variation.

The RFID bridge antenna 10 is positioned between the tag antenna 24 andthe reader antenna 30 such that the RF antenna coil 16, also referred toherein as the “local coil”, receives the modulated electromagneticcarrier signal transmitted by the reader antenna 30. The carrier signalis conveyed through the electrical conductor 20 and is received by theother RF antenna coil 18, also referred to herein as the “remote coil”,where the signal is then transmitted to the tag antenna 24. The bridgeantenna 10 thus allows wireless data communication between the tag 12and the reader 14 at distances “d” greater than that which would not bepossible without the RFID bridge antenna 10.

The two RF antenna coils 16, 18 may each be formed from one or moreloops (turns) 34 of conductive material suitably disposed on a substrate36, and may include a charge storage element (e.g., a capacitor) 38electrically connected across the loops 34. The loops 34 and the chargestorage element 36 are adhered to, imbedded in, or otherwise attached tothe substrate 36. It is also contemplated that the RFID bridge antenna10 may be formed from one or more loops 34 without the charge storageelement 38.

The substrate 36 may be formed from any convenient material. Forexample, the substrate 36 may be formed from a printed circuit board,plastic, paper, cardboard, nylon, and the like. As will be described infurther detail hereinafter, the substrate 36 may form part of a packageto allow data communication between a tagged item disposed in thepackage and a reader external to the package.

The loops 34 of conductive material may be formed using any convenientmeans. For example, the loops 34 may be formed from one or more wires orfrom a stamped or etched conductive material (e.g., a metal or metalalloy) attached to the substrate 36. It is also contemplated that theloops 34 may be formed from an electrically conductive ink applied tothe substrate 36. The ink may be applied using any conventional method,such as spraying, screening, painting, and the like. For example, theelectrically conductive ink may include any of a number of thermosettingor thermoplastic highly conductive silver inks manufactured by DowCorning Corporation of Midland, Mich. Advantageously, the use of aconductive ink to form the loops 34 allows the bridge antenna 10 to beapplied to any number of different surfaces. It is also believed thatthe use of a conductive ink to form the loops 34 will reduce the cost ofthe bridge antenna 10 to below that possible where the loops 34 areformed from a wire or etched conductive trace.

The charge storage element 38 may be formed from a surface-mounteddevice (e.g., an SMT capacitor) attached to the substrate 36.Alternatively, the charge storage element 30 may also be formed alongwith the loops 34 as part of a stamping or etching process (e.g., formedfrom a metallic trace). It is also contemplated that the charge storageelement 38 may be formed on the substrate 36 along with the loops 34 bythe application of the conductive ink.

As best shown in FIG. 3, the loops 34 of the RFID bridge antenna 10extend in a plane defined by the substrate 36. The tag antenna 24 andreader antenna 30 may be similarly formed as generally planar loopantennas. In the embodiment shown, the two bridge antenna coils 16, 18are each positioned so as to face the tag antenna 24 and the readerantenna 30, respectively, in a generally spaced apart, parallel relationsuch that the off-plane orthogonal axis of the antenna coils 16, 18 isgenerally aligned with those of the tag antenna 24 and reader antenna30. However, as depicted in both FIGS. 1 and 2, the two bridge antennacoils 16, 18 may be off-set at most any angle desired in either ahorizontal or vertical plane owing to the flexible properties of theconductor or coaxial cable 20. This is a decided advantage of the RFIDbridge antenna enabling its use in extending the distance or gap overwhich the reader 14 may communicate with a tag 12 in many differentapplications. For example, it is possible with the bridge antenna for areader 14 to communicate with a tag 12 attached to an object that isplaced at a distant or remote location inside a package wherein theflexible cable connecting the two coils 16, 18 is able to follow, insome cases, a tortuous path between and/or around other objects in thepackage.

Preferably, the two RFID bridge antenna coils 16, 18 are coupledtogether electromagnetically by a low radiation loss conductor 20, suchas a shielded coaxial cable (e.g. a 50 ohm coax) and should bothresonate at substantially the same frequency in order maximizetransmission efficiencies between the two RF antenna elements. The twocoils 16, 18 should also be tuned to approximately the same resonatefrequencies as the tag and reader antennas 24, 30, respectively. The tagand reader antennas 24, 30 as well as the two coils 16, 18 may all betuned by employing a charge storage element 38 (e.g. a capacitor) ofsuch value as to substantially equal the inductive reactance of thecoils and thus cause the antennas to resonate at the desired frequency.The antennas may also be tuned by changing the number of loops or turns34, and/or by changing the cross-sectional area of the conductivematerial forming the loops 34.

In the embodiment of FIG. 3, the tag 12 is depicted as a passiveradio-frequency identification (RFID) tag, which communicates data byway of electromagnetic field coupling between the tag antenna 24 and theremote RF coil 18 of the bridge antenna 10. Within the tag 12, datastorage and processing as well as radio frequency (RF) communicationsfunctions are typically performed by one or more integrated circuitchips 26. For example, the tag 12 may include: a memory core (e.g., anEEPROM) 40, which stores data associated with an object 42 (e.g., amodule or CRU) to which the tag 12 is attached; a power supply regulator44, which rectifies and otherwise conditions alternating current inducedin the tag antenna 24 by the time-varying RF carrier signal provided bythe reader antenna 30 for use in the tag as a direct current powersource; and receiver/emitter modules 46 and 48 (e.g., compatible withthe ISO 14443 standard) for demodulating and decoding incoming data fromthe received RF signal and superimposing outgoing data on the RF signalby load variation, respectively.

While FIG. 3 depicts a passive RFID tag, it is also contemplated thatthe tag 12 may include an active or partially active RFID tag, whichuses a battery (e.g., a thin power source) to provide all or part of theoperating power for the tag 12.

The reader 14 includes a transmitter 50 that generates the time-varyingRF signal transmitted by the reader antenna 30. As a result ofelectromagnetic coupling between the tag antenna 24 and the readerantenna 30, a portion of the RF signal transmitted by the tag antenna 24enters the reader antenna 30 and is separated from the transmittedsignal by a detector (e.g., an envelope detector) 52. The separatedsignal is passed to a receiver 54, where it is amplified, decoded andpresented via a microcontroller 56 to the host processor 28.

With the RFID bridge antenna 10 connected between the tag antenna 24 andthe reader antenna 30 as shown in FIG. 3, an electromagnetic RF carriersignal generated by the reader 14 is transmitted by the reader antenna30 and is received by the local RF coil 16 of the bridge antenna 10.Assuming the transmission line provided by the cable 20 is balanced,that is, the load impedance equals the characteristic impedance of thecable (e.g. 50 ohms), the conductor will act as if it were infinitelylong and the RF signal that appears at the opposite end of the cable,namely at the remote RF coil 18, will be of substantially equal strengthas compared to the input signal. In other words, there should be littleif any loss of signal if the transmission line is correctly terminated,regardless of the length of the cable 20. It has been determined thatthis use of a low loss cable 20 in the RFID bridge antenna 10 allows thetag 12 to be powered by the carrier signal transmitted by the readerantenna 30 at distances greater than that which would be possiblewithout the bridge antenna 10, thus allowing wireless data communicationbetween the tag 12 and the reader 14 at these greater distances. Indeed,it has been determined that the RFID bridge antenna 10 can more thandouble the range over which the tag 12 and reader 14 can communicate.Typically, the separation between the tag and reader in ordinaryapplications (i.e., without the bridge antenna 10) has been about 5 mmto 30 mm and in some cases up to 100 mm. It has been shown, however,that a high enough degree of efficiency can be achieved with the bridgeantenna 10 such that a remote tag can communicate with a reader over adistance as much as 600 mm from the tag.

FIG. 4 shows an embodiment in which the RFID bridge antenna 10 isemployed as an extension of the reader or coupler 14. In this case, asingle reader 14 is placed inside an enclosure 58 together with twoobjects 60, 62, each of which is positioned at a distant or remotelocation from each other, for example, at opposite ends of theenclosure. The enclosure 58 may be a shipping package or a machine, suchas a printing apparatus, and the objects may be consumables, such as inkcartridges, or more generally customer replaceable units, CRUs. Theobjects 60 and 62 each have a separate tag 64 and 66, respectively,which contain electronic data identifying the objects. The reader 14 isplaced proximate to one of the objects 60 and receives data relative tothat object directly from its tag antenna 64. The reader 14 alsoreceives data from the tag 66 relative to the object 62 by means of theRFID bridge antenna 10. As shown, the bridge antenna 10 has its localantenna coil 16 positioned proximate to the reader 14 while its otherremote coil 18 is placed proximate to the tag 66 on the remote object62. The reader 14 receives this data via the signal carried from onecoil to the other by the flexible cable 20, extending the distance overwhich the tag 76 can communicate with the reader 14. The bridge antenna10 may be supported by any suitable means such as by using supportingsubstrates 36 for each of the coils 16, 18 as shown in FIG. 3. Forsimplicity, the reader antenna 30 is not shown in the view of FIG. 4. Itwill be seen then that the RFID bridge antenna greatly enhances theutility of the reader or coupler 14 in communicating with both tags 64,66. The RFID bridge antenna, in this case, is an “extension” of thereader or coupler 14. This is possible because the coupling efficiencythat can be achieved with the bridge antenna is easily high enough topower a remote tag 66. It should also be noted that the bridge antennamakes possible the use of only one reader or coupler in installationswhere two or more tags or objects are involved. This approach would beconsiderably less expensive and require considerably less softwarecomplexity than having a second coupler in the package or machine.

FIG. 5 depicts a more complicated installation of multiple RFID bridgeantennas for obtaining data relative to multiple objects or CRUspositioned inside separate enclosures. In the illustrated installation,two objects or CRUs 68, 70 are shown placed inside an inner enclosure 72(shown in phantom) which may be a machine, such as a printing apparatus,for example, the inner enclosure 72 being contained within an outerenclosure 74 (also shown in phantom) which may be a shipping carton forthe machine. Ordinarily, with the present state of the art, it would beextremely difficult, if not impossible, to obtain data relative to theseobjects 68, 70 using a reader or coupler 76 that is external to theouter package 74. In this case, however, obtaining such data is madepossible through the use of either one of two separate RFID bridgeantennas 78, 80 and optionally a third bridge antenna 82. The firstbridge antenna 78 has its local antenna coil 84 attached to the exteriorsurface of the outer enclosure 74 and its remote coil 86 positionedproximate to the tag 88 mounted on the remote object or CRU 68. The twocoils 84, 86 are coupled electromagnetically by the shielded, flexiblecable or coax 90. The second bridge antenna 80 has its local antennacoils 92 also attached to the exterior surface of the outer enclosure 74while its remote antenna coil 94 is positioned proximate to the tag 96mounted on the other object or CRU 70. The object 70 is located closerto the external reader 76 but in a more remote position with respect tothe object 68. The two coils 92, 94 are coupled together by theshielded, flexible cable or coax 98. Optionally, the third RFID bridgeantenna 82 has one of its antenna coils 100 also positioned proximate tothe tag 96 mounted on the object 70 while its other antenna coil 102 ispositioned proximate to both the tag 88 on the remote object 68 and theantenna coil 86 of the first bridge antenna 78. The two antenna coils100, 102 are similarly coupled electromagnetically by the flexible cableor coax 104.

At any time during shipping, storage or use of the objects 68, 70, datarelative to the two objects may be received by placing the reader 76 inclose proximity to either one of the RF antenna coils 84, 92 on thesurface of the outer enclosure 74. When placed next to the antenna coil84, the reader 76 can receive data stored in the tag 88 relative to theobject 68 via the first RFID bridge antenna 78 and, in a separateoperation, it can also receive data stored in the tag 96 relative to theobject or CRU 70, via the third RFID bridge antenna 82. In a similarfashion, the reader 76 can receive data stored in the tag 96 relative tothe object 70 when placed next to the antenna coil 92 and, in a separateoperation, it can also receive data stored in the tag 88 relative to theobject 68 also via the third bridge antenna 82. It is possible with thissame arrangement to link a number of tags together using multiple bridgeantennas in series to greatly extend the distance over which a singlereader can communicate with multiple tags attached to objects remotelydispersed inside a package or machine. Many other RFID bridge antennaarrangements aside from those illustrated in FIGS. 4 and 5, includingthose using bridge antennas in parallel, are possible as will readilyoccur to those skilled in the art.

Although not shown in FIG. 5, the bridge antenna coils may be supportedby any suitable means such as by mounting them on substrates as shown inFIG. 3, by printing them on labels or by embedding the coils in PC boardmaterial, for example. The two external mounted antenna coils 84, 92 forthe two bridge antennas 78, 80 used in the installation of FIG. 5 can besuitably imprinted on labels which are then affixed to the surface ofthe outer enclosure 74 which may be a package or carton. They can alsobe printed directly onto the outer surface of the same package orcarton.

As used herein, a label includes any identifying or descriptive markerthat may be attached to an object. For example, the label may include apackaging label, which includes text or other visual informationrelating to a package or carton.

The antenna coils used in a typical RFID bridge antenna may generallyconform to the ISO Standard 14443-2B requirements and will usuallyresonate at about 13.5 MHz, for example. Such a resonate antenna coilcan be made using a standard antenna wire about 100 centimeters longhaving a cross-section of about 1 mm, coiled into 6 substantiallyrectangle shaped loops, spaced about 0.7 centimeters apart, andincluding a capacitor connected across the loops of a value betweenabout 0 and 120 pF. The two RF antenna elements which make up the RFIDbridge antenna are each positioned relatively close to the respectivetag and reader antennas during operation of the RFID system, typicallyfrom about 5 to about 20 mm, for example. However, with the RFID bridgeantenna in place, separation between the tag and coupler has beensignificantly increased to distances of from about 50 to about 300 mm.

As illustrated in FIG. 5, one or more RFID bridge antennas 78, 80 may beused to allow data communication between tags 88, 96 secured to objects68, 80 disposed in an enclosure or package and a reader 76 that isexternal to the enclosure. In these installations, the bridge antennas78, 80 are positioned between the tags 88, 96 and the reader 76 toincrease the data communication range between the tags and the reader.As a result, data communication between the tags and reader can takeplace through the enclosure or package, without having to remove theobjects.

As used herein, a package includes any container in which something ispacked for storage or transportation. While FIG. 5 depicts the package74 as a box, it is contemplated that the package may include anyone ormore of: an envelope, a wrapper, a pallet, a carton, a can, a jar, atray, a trunk, a sleeve, a cargo container, and the like.

FIG. 6 shows a pair of cylindrical containers or bottles 106, 108,suitable for packaging a liquid product, such as ink, for example,wherein each container is provided with a tag 110, 112, respectively. Inone case, the tag 110 is affixed to the side wall 114 of the container106 while in the other case, the tag 112 is affixed to a removable cap116. The cap 116 itself is of a conventional design having generallycylindrical side walls 118 and a generally flat top surface 120. The tag112 including its associated tag antenna 122 is affixed, imbedded orimprinted on the top surface 120 of the cap 116.

The ink container 106 is generally used or stored in a separatecompartment within a printing machine along with its tag 110 which beingon the side wall 114 of the container 106, is generally inaccessible andmust be removed from the compartment before any data relative to the inkproduct can be ascertained using a reader. This problem is essentiallyavoided when using the container 108 equipped with a cap 116 having atag 112 affixed to its top surface 120 as shown in FIG. 6. Since, inmost cases, the container 108 is stored either standing or resting onits side, the cap 116 with its tag 112 is readily exposed and easilyaccessible to a reader or coupler.

Such an arrangement is shown in FIG. 7 wherein the ink container 108 isstored on its side within the storage area 122 of a cabinet or printingmachine, for example. The storage area 122 is basically defined by aframework, indicated generally at 124, and includes a flat panel door126 which is hingeably mounted to the framework 124. When the door 126is swung open as shown in FIG. 7, the cap 116 and associated tag 112 areeasily accessible, permitting communication with the tag 112 using aportable reader or coupler, for example. However, as also shown in FIG.7, a reader 128 may be mounted inside the storage area 122, forinstance, in a position just below the ink container 108. In thisembodiment, the reader 128 communicates with the tag 112 through the useof an RFID bridge antenna 130 mounted onto the inner side 132 of thedoor 126. The bridge antenna 130 comprises two antenna coils 134, 136suitably affixed to the inner side 132 of the door 126. The two coils134, 136 are mounted in spaced apart, co-planar relation on the door andare connected together by a flexible cable or coax 138. The antennacoils 134, 136 are spaced apart a sufficient distance from one anothersuch that they generally align themselves with the tag 112 and thereader 128, respectively, when the door 126 is closed. The bridgeantenna 130 may be affixed to the inner surface 132 of the door 126 byany suitable means such as by gluing directly to the door or byimprinting the antenna coils onto an insulating substrate which is thenattached to the door 126.

FIG. 8 shows an embodiment of an RFID bridge antenna 140 wherein thesubstrate is an electrically non-conductive or insulating PC board 142.The bridge antenna 140 has two coils 144, 146 imbedded or printed ontothe flat planar surface of the board 142. The coils 144, 146 arepositioned in the same spaced apart relation but, in this instance, thecoils are connected together by two separate or spaced apart, flat,narrow, electrically conductive strips 148, 150 which are also imbedded,printed or otherwise incorporated onto the surface of the PC board 142.In this embodiment, the two strips 148, 150 together constitute a lowloss, open twin lead transmission line similar to conventional twin leadTV cable which can be easily incorporated into a PC board byconventional methods. The two strips 148, 150 transmit RF signalsbetween the two coils 144, 146 which are electrically substantially 180degrees out of phase with one another and thus effectively cancel anyradiation losses that may occur. This concept of imbedding or printingan open RF transmission line directly onto a PC board for transmittingRF signals from an RF component on a PC board is believed to have manyuseful advantages in the electronic field aside from its use in theinstant RFID bridge antenna.

The use of low loss, open twin lead transmission line in an RFID bridgeantenna such as illustrated in FIG. 8, for example, is acceptable inimplementations conforming to International Standards organization (ISO)Standard 14443-2B at about 13.56 Mega-Hertz (MHz) for communicating dataover distances of up to about 30 mm. However, at higher frequencies, itmay be more suitable to employ “strip line” as the transmissionconductor in the RFID bridge antenna.

It should also be noted that the RFID bridge antenna disclosed herein isnot limited to the use of only two RF antenna elements such as shown inFIGS. 1 and 2 and may incorporate other types of antenna assemblies suchas a “Y” configuration, for example. The difficulty with these moreelaborate bridge antenna configurations is that of impedance matching sothat the use of devices such as a circulator may be called forparticular at the higher frequency regimes that may be contemplated.

As used herein, an object includes any tangible item to which a tag 12may be attached. As previously noted, the object may include areplaceable module for a machine. For example, FIG. 9 is a schematicdepiction of a machine 152 including replaceable modules 154′ and 154″,also known as “Customer Replaceable Units” or CRUs. Attached to each ofthe modules 154′ and 154″ is a tag 12, which is configured as a CRUM(Customer Replaceable Unit Monitor). The memory core in each CRUM (tag)12 retains data relevant to the identification, function, andperformance of the respective module 154′ or 154″. Because it includes anon-volatile memory, the CRUM 12 can act as a “scratch pad” forretaining the data stored therein, which travels with the replaceablemodules 154′ and 154″, even when the modules are not installed in themachine 152.

The operation of the machine 152 is generally controlled by a controller158, which may include one or more microprocessors, application-specificintegrated circuits (ASICs), or other signal processing devices encodedwith instructions to operate the machine 152. When the modules 154′ and154″ are installed in the machine 152, data is communicated between theCRUMs 12 and the controller 158 via a reader (coupler board) 160 havinga reader antenna 162, which operates in a similar manner to the reader14 described herein above. Communication between each of the CRUMs 12 ismade possible, in this instance, by the two RFID bridge antennas,indicated by blocks 164, 166, interposed between each CRUM 12 and thecoupler board 160, via its antenna 162, in a manner similar to thatillustrated in FIG. 4, for example. In addition, data may becommunicated between a device 168 external to the machine 152 and one orboth of the modules 154′ and 154″ and the controller 158. Controller 158may also communicate with users through a user interface 170 or througha network connection 172, such as over phone lines or the Internet.

For purposes of discussion herein, the machine 152 is depicted as aprinting apparatus, such as a digital printer of the ink jet or “laser”(electrophotographic or xerographic) variety, or a digital or analogcopier, and the modules 154′ and 154″ are depicted as including hardwaredevices related to printing (printing hardware), such as a markingmaterial supply module and a marking device module, respectively. It iscontemplated, however, that the machine 152 may be any electrical,electronic, mechanical, electromechanical device configured to performone or more functions, and the modules 154′ and 154″ may be anycomponent, group of components, system, or subsystem of the machine 152.The word “printer” as used herein encompasses any apparatus, such as adigital copier, bookmaking machine, facsimile machine, multi-functionmachine, etc. which performs a print outputting function for anypurpose.

In the embodiment of FIG. 9, sheets on which images are to be printedare drawn from a stack 174 and move relative to the marking devicemodule 154″, where the individual sheets are printed upon with desiredimages. The marking material for placing marks on various sheets bymarking device module 154″ is provided by marking material supply module154′. If machine 152 is an electrostatographic printer, marking materialsupply module 154′ may include a supply of toner, while marking devicemodule 154″ may include any number of hardware items for theelectrostatographic process, such as an image receptor (photoreceptor)or fusing device. In the well-known process of electrostatographicprinting, the most common type of which is known as “xerography,” acharge retentive surface, typically known as a photoreceptor, iselectrostatically charged, and then exposed to a light pattern of anoriginal image to selectively discharge the surface in accordancetherewith. The resulting pattern of charged and discharged areas on thephotoreceptor form an electrostatic charge pattern, known as a latentimage, conforming to the original image. The latent image is developedby contacting it with a finally divided electrostatically attractablepowder known as “toner.” Toner is held on the image areas by theelectrostatic charge on the photoreceptor surface. Thus, a toner imageis produced in conformity with a light image of the original beingreproduced. The toner image may then be transferred to a substrate, suchas paper from the stack 174, and the image affixed thereto to form apermanent record of the image.

In the ink-jet context, the marking material supply module 154′ includesa quantity of liquid or solid ink, and may include separate tanks fordifferent primary-colored inks, while marking device module 154″includes a printhead. In either the electrostatographic or ink jetcontext, “marking material” can include other consumed items used inprinting but not precisely used for marking, such as oil or cleaningfluid used in a fusing device. Of course, depending on a particulardesign of a machine 152, the functions of modules 154′ and 154″ may becombined in a single module, or alternatively, the marking device maynot be provided in a easily replaceable module such as 154″. Further,there may be provided several different marking material supply modules154′, such as in a full color printer. In general, it is contemplatedthat the machine may include one or more replaceable modules, and it isexpected that, at multiple times within the life of machine 152, one ormore of these modules need to be removed or replaced. In the currentmarket for office equipment, for example, it is typically desirable thatmodules such as 154′ and 154″ be readily replaceable by the end user,thus saving the expense of having a representative of the vendor visitthe user.

There are many different types of data that can be stored in the tag orCRUM 12. For example, U.S. Pat. No. 6,016,409 issued Jan. 18, 2000 andentitled “System For Managing User Modules in a Digital PrintingApparatus”, which is incorporated by reference herein in its entirety,describes various data that may be stored in a CRUM and variousfunctions that may be performed using this data. Advantageously, usingthe RFID bridge antenna 10 in the manner described with reference toFIGS. 3-9 allows this data to be read from, or written to the CRUM 12from a distance further than would otherwise be possible without thebridge antenna. With the embodiments of FIGS. 3-7 this data can be readfrom, or written to the CRUM 12 when the modules 154 are packaged fordelivery or storage. Depending on the data stored in the CRUM 12, thiscould be used in many useful ways.

For example, the CRUM 12 could retain a serial number of the particularmodule. Using the RFID bridge antenna 10, identification of the packagedmodule by the serial number can be determined by the reader 14 withouthaving to remove the module from the package, for example. Also, theserial number as read by the reader 14 can be used to verifyauthenticity of the module, thereby identifying any counterfeit modulespackaged in authentic packages. The serial number as read by the reader14 can also be useful for inventory tracking, batch identification, andthe like.

In other types of CRUM systems, the CRUM 12 can further act as an“odometer” to maintain a cumulative count indicating use of the module.For example, where the module is to be used with a printing apparatus,the count may indicate the number of prints which have been output usingthe particular module. Using the RFID bridge antenna 10, this count maybe read from a packaged module to determine whether the module is new orrefurbished. Similarly, the CRUM 12 may store one or more thresholdvalues (e.g., maximum number of prints, etc.) against which the count iscompared to determine the health of the module. Using the RFID bridgeantenna 10, these threshold values may be read from or written to theCRUM 12 using the reader 14 while the module remains packaged.

Another type of data which may be stored in a particular location in thenon-volatile memory of the CRUM 12 may relate to specific performancedata associated with the module, so that the module can be operated inan optimal, or at least advisable, manner. For instance, in the ink jetcontext, it is known to load data symbolic of optimal voltage or pulsewidth in the CRUM 12, so that the particular module may be optimallyoperated when the module is installed. In the xerographic context, it isknown to load into a CRUM module specific data such as relating to thetested transfer efficiency of toner from a photoreceptor to a printsheet: This information is useful for an accurate calculation of tonerconsumption. Using the bridge antenna 10, this performance data may beread from or written to the CRUM 12 using the reader 14 while the moduleremains packaged.

Other types of data which may be included in the non-volatile memory inCRUM 12 include one or more serial numbers of machines, such asprinters, in which the particular module has been installed. This may beuseful for tracing faults in the module or among a population ofmachines. Also, if the particular module is intended to beremanufactured, another useful piece of data to be loaded into thememory can be the date of the last remanufacture of the module, as wellas a code relating to some detail of the remanufacture, which may besymbolic of, for instance, a location of the remanufacture, or thespecific actions that were taken on the module in a remanufacturingprocess. Again, the RFID bridge antenna 10 allows this information to beread from or written to the CRUM 12 using the reader 14 while the moduleremains packaged.

In yet another example, referring again to FIG. 9, other types of datawhich may be included in the non-volatile memory in the CRUM 12 are usedby the controller 158 to configure machine 152 option attributes forenabling or disabling various optional features of the machine ormodule. These option attributes may be associated with a particular userof the machine (e.g., permissions provided to a person using the copier)or may be associated with the machine in general (e.g., speed and/orvoltage settings associated with the country in which the machine isused, optional features available under a sales contract or leaseassociated with the machine, etc.). Examples of these optional featuresmay include but are not limited to: device/machine speed; machine standalone mode or network connected mode; scanning enabled; scan to email;scan to Internet Fax; network server Fax enabled; job based accounting;etc. Other data that may be stored in the CRUM may include softwareupdates, settings updates, and the like that are used by the controller158. The bridge antenna 10 allows data communication between the CRUM 12and the reader 14 while the module is in the package, thus allowing anyof this data to be read from or written to the CRUM 12 without removingthe module from the package 58, 74. Advantageously, this allows genericmodules to be manufactured and packaged, with the CRUMs 12 of thesegeneric modules later being programmed for particular applications asthey are needed.

It should be understood that any of the features, characteristics,alternatives or modifications described regarding a particularembodiment herein may also be applied, used, or incorporated with anyother embodiment described herein.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Variouspresently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims.

What is claimed is:
 1. A machine incorporated within a housing having anon-conductive access door, comprising, in combination: at least oneRFID bridge antenna positioned on an interior of said access door whichacts as a non-conductive substrate therefor, said RFID bridge antennaincluding two spaced-apart antenna elements coupled by an electricalconductor; one or more serviceable modules incorporated within saidhousing, at least one of said modules having an RFID tag mounted thereonand positioned in proximity to one of said antenna elements when saidaccess door is closed; and an RFID reader incorporated within saidhousing and positioned within proximity of the other antenna elementwhen said access door is closed, such that the RFID bridge antennapermits the RFID reader to read data stored within said RFID tag, andwherein said access door when open permits servicing of said one or moreserviceable modules.
 2. The machine of claim 1, wherein said one or moreserviceable modules includes printing hardware.
 3. The machine of claim2, wherein said one or more serviceable modules is one of: a markingmaterial supply module and a marking device module.
 4. The machine ofclaim 3, wherein the marking material supply module includes at leastone of: toner, liquid ink, solid ink, oil, and cleaning fluid.
 5. Themachine of claim 3, wherein the marking device module includes at leastone of: an image receptor, a fusing device, and a printhead.
 6. Themachine of claim 1, wherein the RFID bridge antenna is imprinted on theinterior of said access door using electrically conductive ink.
 7. Themachine of claim 1, wherein the RFID bridge antenna is formed on asubstrate that is then mounted on the interior of said access door.